• Journal of Industrial Technology
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• v.28 no.B
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• pp.81-89
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• 2008

This paper is results of investigating the dominant factors influencing to coefficient of consolidation in horizontal direction of Korean marine clays and their correlations through literature review. From the results of analyzing data obtained from field tests such as piezocone penetration and dilatometer tests as well as laboratory tests, coefficient of consolidation in the horizontal direction was found to increase with increase of stiffness index of soil while it decreases with the increase of dissipation time of pore pressure developed during field tests. In general, the coefficient of consolidation in the horizontal direction tends to increase with increase of undrained shear strength and preconsolidation pressure although correlation between them are relatively low. Friction ratio has a high correlation with coefficient of consolidation in the horizontal direction in case of friction ratio being greater than 1.0. For methods of estimating coefficient of consolidation in the horizontal direction with different testing device, values obtained from methods of P2-logt and DMT-A with dilatometer were quite similar to values from piezocone penetration test. Consistency of soil is quite proportional to coefficient of consolidation in the horizontal direction. Clear correlation between coefficients of consolidation in the horizontal and the vertical directions could not be found. coefficient of consolidation in the horizontal direction estimated from the results of field test tends to be 1.13~3.11 times greater than that obtained from laboratory tests.

• Journal of Industrial Technology
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• v.28 no.B
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• pp.71-79
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• 2008

Reports about coefficients of consolidation in horizontal direction of marine clays located at seven different sites on western and southern coast area in Korea were reviewed and characteristics of them were investigated. As results of analyses, for relation between the depth of ground and coefficients, any trend and correlation between them can not be found since they are more influenced by the nature of geological formation rather than the depth of ground. Dissipation time t50, one of important factors in estimating value of coefficient of consolidation in horizontal direction, was found to be quite related to them. For the correlation between the maximum pore pressure developed and coefficients, coefficient of consolidation in the horizontal direction tend to decrease with increase of the maximum pore pressure whereas the ground water level or static pore pressure do not have any specific correlation with those coefficients. Values of coefficient tends to increase with values of liquid limit, plastic limit and plastic index and thus they are found to be directly influenced by the contents of fines. Values of coefficient of consolidation in horizontal direction are also increased with increases of permeability in horizontal direction and coefficient of consolidation in vertical direction. They were highly correlated between coefficient of consolidation and permeability in horizontal direction while values of coefficient of consolidation in horizontal direction have a relatively low correlation with values of coefficient of consolidation in horizontal direction. Sometimes, coefficient of consolidation in horizontal direction obtained from field tests were estimated 2-3 times greater than those from laboratory tests.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.738-743
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• 2013

Underwater radiated noise is the key in acoustic stealth performance of modern naval ships. The underwater radiated noise predicted by the hull vibration with radiation efficiency cannot give the information of radiation pattern which is essential to the analysis of detection possibility by enemy and to improve the operational performance of the naval ship. The radiation pattern of underwater radiated noise is able to be obtained with radiation efficiency and radiation direction coefficient. In this paper, a new method to extraction the radiation efficiency and radiation direction coefficient is suggested and proved with the simulation and experiment by using cylindrical shell of 70cm diameter in air.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.4
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• pp.80-86
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• 2021

Plastics are widely used in mechanical and other fields due to their light weight, design flexibility, and molding processability. In processing plastics, defective products are mixed and reprocessed to improve production efficiency and reduce costs. In this study, an experiment was conducted to confirm the coefficient of thermal expansion of HDPE during this reprocessing. The coefficient of thermal expansion was measured at different measurement directions and heating rates. As a result, we observed that the coefficient of thermal expansion in the direction perpendicular to the injection direction is greater than that in the horizontal direction.

• Transactions of Materials Processing
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• v.32 no.1
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• pp.35-40
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• 2023

In the case of a wire with a very fine diameter during the multi-stage drawing process, the heterogeneity of the deformation in the radial direction tends to develop strongly as the amount of deformation is accumulated. It is known that the heterogeneity of deformation in the radial direction of the wire is closely related to the process parameters during the multi-stage drawing process. In this study, finite element analysis (FEA) was used to theoretically examine the effect of friction between the surface of the wire and the drawing die during the multi-stage drawing process of Cu-0.2wt%Mg alloy on the deformation heterogeneity developed in the radial direction of the wire. The distribution of effective strain, radial strain, circumferential strain, and shear strain developed in the radial direction of the wire during the multi-stage drawing process was analyzed while changing the friction coefficient, and the results were analyzed and compared for each path and position. The FEA results revealed that the shear strain developed in the radial direction of the wire during the multi-stage drawing process of Cu-0.2wt%Mg alloy showed the most non-uniform distribution and was also severely affected by the friction coefficient.

• KSTLE International Journal
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• v.6 no.2
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• pp.51-57
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• 2005

Surface texturing of tribological applications is an attractive technology of engineered surface. Therefore, reduction of friction is considered to be necessary for improved efficiency of machines. The current study investigated the potential of textured micro-scale grooves on bearing steel flat mated with pin-on-disk. We discuss reducing friction due to the influence of sliding direction at surface pattern. We can indicate lubrication mechanism as a Stribeck curve, which has a relationship between the friction coefficient and a dimensionless parameter for the lubrication condition. It was found that the friction coefficient was changed by the surface pattern and sliding direction, even when surface pattern was the same. It was thus verified that micro-scale grooves could affect the friction reduction considerably under mixed and hydrodynamic lubrication conditions. The lubrication regime influences the friction coefficient induced by the sliding direction of groove pattern. The friction coefficient depends on a combination of resistance force and hydrodynamic.

• The Journal of the Korea Contents Association
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• v.14 no.9
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• pp.362-370
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• 2014

This study measured and analyzed the correlation coefficient between movements of thoracoabdominal tumors and external respiration in a free-breathing state, using cyberknife image guided radiotherapy(IGRT). This study subjects included a total of 30 patients with lung tumors(n=10), liver tumors(n=10) and pancreatic tumor(n=10) who underwent radiotherapy, and the movements of tumors were analyzed using converted log data of the tumor motion tracking system(MTS). In a free-breathing state, In relation to Peason's correlation coefficient between external respiration and lung tumors in the entire treatment process, the correlation coefficient was 0.646(p<0.05) in the cranio-caudal direction, 0.365(p<0.088) in the left and right direction and 0.196(p<0.115) in the antero-posterior direction. The correlation coefficient of liver tumors was 0.841(p<0.000) in the cranio-caudal direction, 0.346 (p<0.179) in the left and right direction and 0.691(p<0.001) in the antero-posterior direction. The correlation coefficient of Pancreatic tumors was 0.683(p<0.000) in the cranio-caudal direction, 0.397(p<0.006) in the left and right direction and 0.268(p<0.127) in the antero-posterior direction. In conclusion, the measurement findings of thoracoabdominal tumor movement using IGRT would be helpful in determining an accurate target volume. Moreover, the analysis of correlation between external respiration and movements of internal tumors would provide important information to correct movements of tumors for diverse radiotherapy techniques.

• Magazine of the Korean Society of Agricultural Engineers
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• v.38 no.2
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• pp.145-151
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• 1996

Wind force coefficients of multi-span arched greenhouses with respect to wind direction of $0^{\circ}$ and $30^{\circ}$ were estimated to give more reasonable coefficient. The conventional and subdivided division types of wind force coefficient distribution diagrams were constructed by using the wind tunnel experimental data. Bending moments on the greenhouses were determined through structural analysis using obtained wind force coefficients, and were analyzed. Because actual wind pressure values on a face of greenhouse varied with locations, the more divisions of wind force coefficient distribution were subdivided, the better distribution type was coincided with actual state. In order to calculate the more accurate section force occurred on the arched greenhouse by the wind loads, it was recommendable that the wind force coefficient distribution should take more subdivision type. The maximum bending moment at the multi-span greenhouse frame at wind direction of $30^{\circ}$ was greater than that at O。, therefore the wind force coefficient at inclined wind direction to the wall was needed to be considered for the multi-span greenhouse structural design.

• Kyungpook Mathematical Journal
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• v.61 no.2
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• pp.269-278
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• 2021

In this paper, we investigate harmonic univalent functions convex in the direction 𝜃, for 𝜃 ∈ [0, 𝜋). We find bounds for |f_z(z)|, ${\mid}f_{\bar{z}}(z){\mid}$ and |f(z)|, as well as coefficient bounds on the series expansion of functions convex in a given direction.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.7
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• pp.948-955
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• 2003

Pressure coefficient in rotating discharge hole was measured to gain insight into the influence of rotation to the discharge characteristics of rotating discharge hole. Pressure measurements were done by the telemetry system that had been developed by the authors. The telemetry system measures static pressure using piezoresistive pressure sensors. Pressure coefficients in rotating discharge hole were measured in longitudinal direction and circumferential direction with various rotating speed and 3 pressure ratios. From the results, the pressure coefficient, and therefore the discharge coefficient, is known to decrease with the increase of Ro number owing to the increase of flow approaching angle to the discharge hole inlet. However, there exists critical Ro number where the decrease rate of discharge coefficient with the increase of Ro number changes abruptly; flow separation occurs from the discharge hole exit at this critical Ro number. Critical Ro number increases with the increase of length-to-diameter ratio, but the increase is small where the length-to-diameter ratio is higher than 3. The decrease rate of discharge coefficient with the increase of Ro number depends on the pressure recovery at the discharge hole, and the rate is different from each length-to-diameter ratio; it has tendency that the short discharge hole shows higher decrease rate of discharge coefficient.